Numerical Simulation And Classification On Geothermal Field Of Lasa-rikaze Railway Tunnels In Yarlungzangbo Canyon Area

Newly-built Lasa-Rikaze railway is located on the southwest of Tibetan Plateau, in the Himalayan geothermal belt. When the railway line passes through the Yarlung Zangbo canyon area, the high temperature of tunnels caused by the geothermal, will greatly influence the constructors’ safety, construction schedule and the investment, even it will determine the actual trend of the railway line.This paper selects Semai-Dazhuka section in YarlungZangbo canyon area as the research area and its geothermal abnormal condition as the object of study. On the basis of lots of literature on the geological background of this area, and combined with survey’s data in the field of Lasa-Rikaze railway, the author systemically analyzed the formation mechanism, related geological background and the manifestation of geothermal. Based on the data from temperature measuring hole, this paper carries out the nonlinear fitting and forecasting of the data by using the method of least squares. And then, with the Kriging Interpolation method, this paper carries out the numerical simulation to the distribution law of geothermal. Based on the above research, this paper selects the geothermal of eight tunnels as the object of study, and then does some numerical simulations with the finite element thermal analysis method. And according to the result acquired from the simulation, this paper puts forward the optimization of line through the zone which is abnormal in geothermal. Finally, this paper proposes an evaluation standard of the geothermal damage in Lasa-Rikaze railway, which also classifies and predicts geothermal damage in tunnels and proposes corresponding prevention measures. This research provides theoretical basis for route selection of Lasa-Rikaze railway in geothermal zone, as well as a reasonable construction scheme standard of tunnels construction.